As the scanner is continuously advancing in manufacturing techniques and its price has dropped to a reasonable level, the scanner now has become an indispensable peripheral device for a standard PC. Owing to the rise of the processing speed of a central processing unit (CPU) in a standard PC and the requirement on high scanning quality for a standard PC user, the image scanning device capable of scanning various kinds of objects has already emerged in the scanner market. For example, an image scanning device which can respectively scan a reflective object (such as a textbook) and a transparent object (such as a film).
Referring now to FIG. 1, the flat-bed image scanning device of the prior art is implemented with using a contact image sensor (CIS) module 11 as the image-pickup module. The CIS module 11 underneath the scanning platform 10 is made up of a RGB light source 111, a rod lens 112, and a sensor chip 113 so as to scan a colored reflective object on the scanning platform 10. While the user tends to scan a transparent object with a flat-bed image scanning device, a transparency adapter (TA) 12 must be provided to be arranged in the flat-bed image scanning device in order to provide a penetrative light. Unfortunately, the transparency adapter (TA) 12 is able to provide a monochromatic light only, and thus it can not be applied to scan a colored transparent object.
Accordingly, the applicant tries to develop a light source module arranged in an image scanning device for solving the problems suffered from the prior art.